Character mistake: Bucky says he read The Hobbit in 1937 when it first came out. But in 1937 he was still living in New York, and The Hobbit was only available in the UK at that time, with fairly limited numbers printed. It wasn't available in America until 1938.
Character mistake: When Rose and her friend board the plane, the stewardess offers them champagne. When she hands them their glasses, it is evident that the wine is a non-sparkling white wine, as there are no bubbles rising in the glasses. This is possibly a mistake by the stewardess, but not one that a professional would be likely to make.
Character mistake: When Samson is playing trivia with Cross' kids right at the beginning of the episode, he asks, "First black mayor of D.C.?" and the son answers, "Marion Barry." John awards him the point while his daughter asks, "Who?" Not the first black mayor of D.C., for sure, since that was his predecessor, Walter Washington. (00:03:30)
Character mistake: In the scene where Captain Sobel is inspecting the soldiers at the beginning of the episode, he goes up to Sergeant Lipton and notices something wrong with his chevrons. Well, in that part, Sergeant Lipton is not standing correctly in the position of attention because he is sort of slouching and his head is in front of his shoulders and the correct position of attention is standing straight up and having your neck behind your shoulders. If he was in the real army, he would have gotten a punishment for not standing at the correct position of attention. (00:09:30)
Character mistake: Near the end, when Michael reveals to Brennen he knows everything about him, he says, "I know everything about Tyler Brennen." Michael emphasizes "Tyler" as if it's a big deal that he knows Brennen's first name. Michael already knew Brennen's first name from the first time he met him, in Season 2, Episode 15 "Sins of Omission."
Character mistake: Searching for clues to identify a suspect, Masuka takes fingerprints from the interior of a truck. Back at the lab, he says he had two dozen prints and they all belong to the same person. Unless the prints are all of the same FINGER, there is no way he could know the prints were all from the same person without a suspect to compare them to. Masuka is a forensic expert and should know better. (00:15:40)
A Remedy To Cure All Ills - S1-E6
Character mistake: King Uther calls the Lady Morgana, Morgause. (00:11:50)
Character mistake: When Walter is saying his father was a scientific pioneer at the university of Berlin, Peter reacts by saying: "Yeah, I know. Who came here in 1933, which is long before the Nazi's ever took power." In fact it is EXACTLY when the Nazi's took power: 30 January 1933. (00:19:00)
Character mistake: In the final episode, Carlos visits Doc in the psychiatric hospital for advice concerning his upcoming marriage to Holly. While talking, Carlos refers to Doc's deceased wife as "Linda", while throughout the series, it has been made very clear that her name was Deborah.
Character mistake: Captain is warning German travelers about poison oak and ivy, but holding up the leaf of an oak tree.
Character mistake: In season 4 episode 13, "Tuesday," when Marshall is meeting with Ulrich, he is both able to understand and reply in German. In season 5 episode 15, "No Hard Feelings," Marshall almost misses the opportunity to change the street light from red to green, because the text is all in German. Jack has to tell Marshall which word is green, indicating that Marshall does not understand the German language.
The King of the Delta Blues - S2-E6
Character mistake: "Are you going to send in the calvary?" is said twice. It should be "cavalry". (00:09:40)
Character mistake: When David encourages the gang to dance at Scott's birthday party, David mistakenly calls Kelly by her actress' name, Jennie Garth. He says, "Scott, you're off, Buddy. Jen, kind of getting into it."
Character mistake: Despite being a Greek mythology buff Maxie Zeus says "Vulcan" when he meant "Hephaestus" the Greek god of fire and the forge when he first spoke with Batman.
Character mistake: Sam encounters Marc Bolan in the club and warns him to "drive carefully", aware of Bolan's future death in a 1977 car accident. However, Bolan never learned to drive and he was actually a passenger in the fatal accident. (00:07:55)
Character mistake: Dr. Kagan, who's a scientist and should definitely know better, points to Earth's solar system on the chart and calls it "our galaxy." This is roughly the equivalent of mistaking a dot this size [.] for the entirety of North America. (00:23:30)
Caleidoscope - S2-E4
Character mistake: The chess set in Dr. Pierce's home office is set up incorrectly. When the men are set up properly, each player has a light colored square in the right-hand corner. The board as it appears in the show is set up so that the light-colored square is in each player's left-hand corner. This "beginner" mistake puts the king and queen in the wrong positions.
Character mistake: Lance and May walk into a bar in Massachusetts. As they enter, the camera pans and shows a large banner on the front window. The banner is advertising "game day" food and drinks. In very large letters the banner shows Boston Red Socks. The actual correct spelling is Boston Red Sox. (00:05:45)
Character mistake: At the end of the scene in the grocery store when Rachel collapses and people run to her aid, the camera pans out to reveal a sign that prominently reveals a sale on "Pop Tards" or possibly "Pop Taros."
Character mistake: Bellamy calls Monty "Murphy" when they get back to the Arc and he is losing oxygen.